module BeEF
  
  module Filter
    
    # check if the string is not empty and not nil
    def self.is_non_empty_string?(str)
      return false if str.nil?
      return false if not str.is_a? String
      return false if str.empty?
      true
    end

    # check if only the characters in 'chars' are in 'str'
    def self.only?(chars, str)
      regex = Regexp.new('[^' + chars + ']')
      regex.match(str).nil?
    end
          
    # check if one or more characters in 'chars' are in 'str'
    def self.exists?(chars, str)
      regex = Regexp.new(chars)
      not regex.match(str).nil?
    end
          
    # check for null char
    def self.has_null? (str)
      return false if not is_non_empty_string?(str)
      exists?('\x00', str)
    end

    # check for non-printalbe char
    def self.has_non_printable_char?(str)
      return false if not is_non_empty_string?(str)
      not only?('[:print:]', str)
    end

    # check if num chars only
    def self.nums_only?(str)
      return false if not is_non_empty_string?(str)
      only?('0-9', str)
    end

    # check if valid float
    def self.is_valid_float?(str)
      return false if not is_non_empty_string?(str)
      return false if not only?('0-9\.', str)
      not (str =~ /^[\d]+\.[\d]+$/).nil?
    end

    # check if hex chars only
    def self.hexs_only?(str)
      return false if not is_non_empty_string?(str)
      only?('0123456789ABCDEFabcdef', str)
    end

    # check if first char is a num
    def self.first_char_is_num?(str)
      return false if not is_non_empty_string?(str)
      not (str =~ /^\d.*/).nil?
    end

    # check for space chars: \t\n\r\f
    def self.has_whitespace_char?(str)
      return false if not is_non_empty_string?(str)
      exists?('\s', str)
    end

    # check for non word chars: a-zA-Z0-9
    def self.alphanums_only?(str)
      return false if not is_non_empty_string?(str)
      only?("a-zA-Z0-9", str)
    end
          
    # check if valid ip address string
    def self.is_valid_ip?(ip)
      return true if ip =~ /^(\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3})?$/
      false
    end

    # check for valid browser details chars
    def self.has_valid_browser_details_chars?(str)
      return false if not is_non_empty_string?(str)
      not (str =~ /[^\w\d\s()-.,;:_\/!\302\256]/).nil? # \302\256 is the (r) character 
    end  

  end
  
end